Mechanical pencil



Oct. 28, 1930. L. c. PlATT A MECHANICAL PENCIL I 2 Sheets-Sheet 1 Original Filed May 21, 1926 Oct. 28, 1930.- L. c. PIATT MECHANICAL PENCIL Original Filed May 21, 1926 2 Sheets-Sheet 2 Snowdon Rial/ Lal/fence C 33M hib GMM/wmf MIM' M- I Patented Oct. 28, 1930 UNITED STATES LAURENCE `(2: PIATT, 0F BUFFALO, NEW YORK ECHANICAL rENeri.

:Application-med lay 21, 1926, 'Serial No. 110,626. Renewed Hatch 17, 1930.

This inventionrelates to a mechanical pencil in whichthe lead is propelled toward and f expelled from the point 4at will, and has for one of its objects'theprovision of a pencll 5-of large capacity for the reserve supply of leads. Heretofore, in many mechanical pencils, the lead has been moved through the instrumentality of a screw actuated p usher whichhas necessarily been so dls'posed 1n the body of the pencil as to decreasethe space capable of devotion to a magazine. In ac cordance 'with the/ present invention lsuch ,pushing mechanism is done away with and the major portion of the body of the pencil l5 is available as ar magazine for the leads.'

With pushing mechanism, it has been necessary,in most instances, to remove ,the lead, manually, from such magazine as the pencil might contain and insert it in a position to ual loading .has been obviated, the mechanie cal loading devices resorted. to havehadto.` be intricate and were'easily disarranged. further object of the present invention is to avoid these disadvantages by the provision of a simple and inexpensive instrl'lmentalityA to feed a lead from the magazine and conduct it to the point. To this end a gravity feed for the leadis provided :and the surface in formed as to permit only one lead at a time to leave the magazine junder the action of gravity and commence itstravel to the point. In the preferred embodiment the surface is given an inverted -substintially conical form and the outlet is disposed at the'axis'andl is be acted 'upon fby the pusher` or where man-g the magazine upon which the leads rest is so cent the point of the pencil and these elements are caused to grip and release thele'ad by manually operable cam devices. More particularly the gripping mechanism comprises a plurality of members capable of rotation with the screw mechanism during the first part of its operation lwhereby the arms may be rotated into and out of contact with camming devices to eiect their engagement and release from alead and capable of relative movement with respect to the screw mechaf nism wher y a movement of translation of, the lead i -e'ected during subsequent movement of the screw mechanism.

These'and other objects of the invention and the'means for their attainmentwill be. more apparent-from the following detailed description of a preferred embodiment illus- :trated in the accompanying drawings, in

which:

Figures 1 ,and 2 are` transverse vertical sectlonal views showmg, on an enlarged` scale, the mechanical pencil according to the present invention and vbringing out in particular detail the construction and coniguration of the lead advancing and retracting mechanism and the manner to which a lead ik is conducted` from the magazine tothe clutch# in devices.

the direction' of the arrows-and showing the gripping or clutclh ingA elements in engagement with a' lead through the instrumentality of cam surfacesn so Figure 4is a view similar to Figure 3 but showing the gripping arms out ofengagement with`V the lead and unaffected by the Calm'. Y IK I Y Figure 5- is` 'a transverse 'sectional view 85 .taken in the plane'indicat'ed by theline 5-5f in Figure 2, looking in the direction of ltlie arrows, and showing details of the 'asselialglyf- .of the component parts.'

Figure 6 isa sectional viewtaken'fin a 9b' igure 3 is a transverse sectional view- 75, taken in the plane indicated by the line 3*-3 YAYin Figure 2, looking in transverse plane indicated bythe line 6-6 in 'Figure 2, looking in the direction of the arrows and showing the magazine full of leads and the `outer casing forming part of the 4 screw mechanism.

Figure 7 1s a vertical sectlonal v1ew s1m1- 4lar to the lower part of Figure 2 but at right angles thereto, taken in the plane indicated by the line 7--7 in Figure 2 and looking in the dlrection of the arrows and showing partieularly the threads on the gripping arms Iby which the lead is firmly retained therebetween.

Figure 8 is a view showing the pencil ac` cording to the present invention about natural size. l

. Most mechanical pencils heretofore provided-have required the use of pushing mechanisr'nlwithin the body of the pencil to effect a movement of translation of the lead and their .construction has generally been such as to necessitate the manual removal of `a lead from al magazine and its insertion in operative relation to the pusher.- Where the manual steps have been obviated, complicated and intricate mechanism has been reits travel to the tip e which is-adapted to yieldingly engage the lead by being slotted as at e instead of being rifled as in some pencils to contribute to the positioning of the lead as will be understood. y The selection and exit of a single lead from the magazine may be accomplished on various ways but it has been 'found most convenient to have the leads in the magazine rest (assuming the pencil held in a vertical position? upon a substantially inverted conical sur -ace d so that the leads will tend to seek the lowermost portion thereof and the lead at the apex can pass outV pf themagazine by entering a passage d2 eading toy gripping, devices which engage the leadfrfom the side intermediate its ends and move it from or toward the point as desired,y Figuresl and 2 illustrate the dispositionof the leads in the magazine with respect tothe feeder or guide d it vbeing understood,

ofcourse, that the leads have been indicated somewhat conventionally as being spaced. They may be in close contact in practice, of course.

The gripping devices are preferably formed 'apair of opposed resilient arms f, f defining a continuation off the passage d2.

Normally the resilient arms are so positioned that ltheir inwardly. serrated 'lead engaging ends'f6 are spaced from one another a distance equal to the diameter ofthe passage cl2 to afford unimpededprogress of the lead to the tip whereby it ma protrude the desired distance therefrom' 1n the first instance. To effect a movement of translation of the lead the serrated portions f of the resilient arms are caused to grip the lead and then the arms themselves are given a movement of translationin the desired direction to effect either propulsion or retraction of the lead. This gripping action is preferably effected by cam surfaces forming the interior -,surface of a 'passage c' in a tip member i into which the tip e is threaded and which in turn is threaded into a.' cylindrical casing member. j housing the magazine and guide member d. Referring to Figures 3 and' 4 it will be seenAthat the diameter'of the passage i varies between the diametrically disposed stops 2 so that the .interior points'z'3 is sucient to allow the prongs f, fto assume their normal position (see Fig. 4) to allow the unimpeded progress of the lead b' therethrough. When, however, the casing (to which the member z" is rigidly seof the passage at the cured.) and the magazine a (withwhich the gripping prongs f, f are carried) are. rotated about their axes relativeto one another, the portions i4 of the passage 1l which are ofreduced diameter are brought into contact with the arms f, f and cause them to move in-v wardlykand grip the lead. vIn order, thereafter, to advance or retract the lead, the arms are given a longitudinal motion in the desired direction. It will be found necessary, therefore, to cause first a rotation of the arms to rip the lead, but this rotation can only conlHO tn'fueI until the arms abut against the stops.

Thereafter, v,only longitudinal motion is possible obviously, whereas, as will be apparent hereinafter the movements of the lead gripping devices are effected by screw mechanism 4involving relative rotational movement between the magazine and the outside casing. In order then that the arms may be first given a rotational movement to bring them into or out of Contact with the camming surfaces and v thereafter only a longitudinal motion, a frictional clutching device, asit'may be called, is interposed betweenl the arms f and the guide member d by which they are carried. The arms, are formed, -for convenience, upon a cylindrical carrier portion f having a flaring or inverted conical top f2 by which it is removably retainedagain'st an inverted conical surface d3 on the guidemember d by the inverted conical enga ing portion g of a nut g which is threade sufficiently on to the threaded extremity d3 of carrier d to retain theparts in engagement 'but yet afford-a sl1d1ng .t between the flaring end fzand the assoclated parts. A lock nut h may also be be termed the casinggroup of parts is e fected by screw mechanism located at the' cated member causes that member to turn' Vwith it bringing the arms into or out o/enthe gagement with the cammiiig surfaces a case may be. After the arms are in Contact with the stops, for instance, further rotation] of the magazine will cause the top f2 to slide over the conical end of the carrier. As the rotation of the magazine is eected by screw mechanism its rotation causes a movement of the magazine longitudinally of th pencil, carrying with it' the bifurcated member which slips over the guide and has only a longitudinal movement. frictional engagement of the flaring top f2 advantage may e taken ofthe resiliency of the metal. To this end it may be slotted as at f, f* and the portions'f' therebetween, which are disposed' 120 apart,.reduced'in thickness to lform resilient members to bear against the conical surface of thenut and 'give sufficient frictional engagement `to cause the bifurcated member to turn with the magazine into and out of contact with the cam surfaces but permitting the flaring top to slip with respect to the guide when the arms contact with the stops.

The relative movement, both rotative and longitudinal, between what may be termed the magazine group ofgparts and what ma upper end of the pencil. 'The capc is the key actuating element of the screw mechanism. It will be lobserved that this cap is inwardly threaded as at c to engage with threads `Va2 formed oxn the outside of the, magazine a. When the cap is screwed `tightlyonto the magazineal rotation of the cap c will obviously cause the rotation with it ofthe magazine a. The casing proper jextends within the cap at the portion of'increased diameter c2 andis inwardly threaded as at j to mesh with the threads on the magazine a". Thus when the cap is turned, the casing j being held stationary in the fingers', the magazine is caused to turn within the casing. AssuminA now that the cap and magazine are screwe tightly together, a rotation of the casing group (relatively speaking)l in a counter- Y clockwise directionlooking at Figure 4, with respect to the magazine group will causethe arms f to move against the stops 2 at the parts of greatest diameter 3. Holding the pencil in asubstantially vertical' direction alead will now feed downwardly out of the magazine and maybepermitted to protrude any desireddegree beyond the point e. To hold. the lead in that position the cap maybe turned in the opposite position still holding the casing in the fingers `.which will cause rotation of the casing group in a clockwise di- To contribute to the.

rection with respect to the maga-zine group and bring the vportion if* of reduced diameter in contact with the arms .f to cause them to grip the lead b (see Figure 3). That degree of pressure incident'to writing may now be brought to bear uponthe lead without dis placing it. When the lead wears further protrusion beyond ,the tip must bei caused. This operation, called propulsion, is effected by turning the c'ap still further and causing further rotation of `thel magazine group./ l This further rotation of the magazine group v causes a longitudinal movement thereof with respect to the casing group by reason of the interengagement of the threads and the arms f,' f holding the lead therebetween are caused to move downwardly vin the passage z' and thus propel the lead throughV the tip. .When the arms have reached the extreme outer or lower up the lead. This is accomplished by turning the cap vin the opposite"l direction leffecting -counterclockwise rotation of the casing group with respect to the magazine group'which allows the arms to spring back to the position shown in Figure 4. Still further rotation of the cap will cause the combined rotative and longitudinal movement ofthe Imagazine along the threads on the casing y' in anupward direction carrying the arms f upward 'in the passage i, the arms abutting 'against the stops 'i2 turning'f with respect to the magazine group as a whole by reason of the loose or swivel connection between the nut g and the carrier f. After the arms have been retracted a suflicient distance the capis turned in the, opposite direction to cause their engagement again with the `lead as before.V

The serrations inwardly on the extremities of thelprongs f, f facilitate this gripping of the lead'. In some situations relative movement of the arms f with respect to the lead in l l While no provision fo an eraser has been illustrated it will be obvious that a place for one may be readily arranged in the ca v By the construction described a mec anical pencil is afforded wherein practically the entire body is available asa magazine for a\ reserve supply of leads and the pencil'l is yprovided with automatic feeding means so arranged as to permit the. leads to leave the magazine' one at a time as` a precedin 'lead is used up. V'The lead is propelled and expelled as desired by 'means ofi screw mechanismI through the instrumentality of lead engag-l ing elements which` ae disposed adjacent the tip in order to afford maximum space `for a magazine.

gagement with the leads and no limitation is intended by the phraseology orthe disclosure of the foregoing specification except as indicated inthe appended claims.

What I claim is i 1. In a mechanical pencil, in combination,

vpa casing, a ca p at the upper end of the casing, a magazinel having an inverted conical bottom formed with anaxial aperture for the passage' of a lead to the tip and an inverted frusto-conical lower surface, a threaded connection between the magazine and the cap and casing, respectively, a lead gripping element formed with arms and having an inverted substantially conical face, means to support said face in frictional engagement with the lowersurface on the magazine, and camming means disposed within the casing and with which the' arms of the gripping element contact.

2. In a mechanical pencil, in combination, a casing, a cap at theupper end of the casing, a magazine having an inverted conical bottom formed with an axial aperture for the passage of a lead-to the tip and an inverted conical lower surface, a threaded connection between the magazine and the cap and casing, respectively, a bifurcated lead gripping element having an inverted conical face,

a nut to support said conical face in frictional engagement with the conical ,lower surface on the magazine, said casing being formed with cam surfaces with which the arms of the bifurca'tedmember Contact, and a stop for the bifurcated meinber. 4

3. In a mechanical pencil, a casing comprising a cylindrical portion, an end portion having an axial passage whereof the surface is formed with opposed camy faces' and stops dividing said faces and a tip, a cap at the upper end of the casing, a cylindrical magazine, screw connectionsv between the magazine and the cap and casing respectively, a magazine bottom element secured to the magazine and formed with an inverted conical upper surface and an axial aperture land an inverted conical bottom surface, a bifurcated gripping element having an inverted conical upper end and whereof the arms are disposed within the passage in the end portion of the casing, and a nut to support thevend in fric- Yingyanaxial passage whereof they surface is formed-,With opposed cam faces'and stops dividing said faces and a tip, a cap at the upper'end ofrthe casing, a cylindrical magazine, screwconnectlons between the magmagazine bottom element secured to the magy azine and formed with an inverted conical -upper surfaceand an axial aperture and an inverted conical bottom surface, a bifurcated gripping element having an 'inverted conical upper end and whereof the arms arexdisposed within the passage Iin the end portion of the casing, a nut to support the 'end in frictional engagement with said bottom surface, said arms being formed with serrations inwardly' connections.

5.' In a mechanical pencil, in combination, a casing, a magazine having a bottom formed lwith an axial aperture for the passage of a lead-to the tip and a lower friction surface thereon, a connection between the magazine and a lead engaging element', a'lead gripping element, a friction surface on the upper portion-thereof engaging the friction surface o f the magazine, meansto support said surfaces in frictional engagement with'e'ach other, and meansto cause the gripping element -to engage the lead. l

6. In a mechanical pencil, in combination, a casing,l a relatively rotatable magazine, a (connection between the casing and magazine to causethe magazine to be moved axially upon-.relative rotation of the magazine and casing, a passage for a lead from the magazine to the tip, gripping elements for the leadcarried within the casing, and clutching means between the magazine and gripping means mounted on the magazine and gripping elements for connecting the same l together.`

7. In a mechanical pencil, in combination, a casin'g,I a magazine movable longitudinally 5 with respect to the casing, a connection betweenthe casing and magazine to cause the maga ine to be moved axially upon relative rotatlon of the magazine and casing, a passage fo'r a lead from the magazine to the tip, means within the casing to grip the lead, and clutchinggmeans between the magazine and gripping'means mounted on the magazine lof a pitch equalto the pitch of the screw and the gripping elements for connecting to be movedfaxciallyupon relative rotation of the magazine and casing, a passage for a lead fromdzhej-magazine to the tip, gripping elementsfr the lead carried within the casing, and vclutching Ameans 'between the magazine and gripping means mounted on the lower end off the magazine and the gripping elements for connecting the same together.

9. In a mechanical pencil, incombination, I

-a casing, means threaded thereon .to engage a lead frictionally to prevent the-lead from falling from the casing, means therein through which the lead is advanced to the azine andthe cap and casing respectively, a means .threaded on y*the casing, rotatable means to grip the lead, and meansto cause the gripping means to engage the lead in the rotation of such meansin one' direction to advance the lead and to disengage the lead in the rotation of the gripping means in the opposite ldirection at any position of the gripping means withrespect to the casing.

This specification signed this 18th day of May, A. D. 1926." A

LAURENCE C. PIATT.- 

